Silver nanoparticles were synthesized by a bio-reduction method which using an aqueous extracted solution of mullein leaves as a reducing and stabilizing agent. The effects of synthesis parameters such as reaction time, temperature and concentration of leaves-extracted solution were studied on the properties of biosynthesized silver nanoparticles. The formed silver nanoparticles were characterized by scanning electron microscopy which is equipped with energy dispersive X-ray spectroscopy, transmission electron microscopy, and X-ray diffraction. The formation of silver nanoparticles at different condition was followed by UV-Vis absorption spectroscopy. The electron microscopy images were confirmed by the formation of monodisperse silver nanoparticles with a spherical shape and their average size is around 30nm which was confirmed with X-ray diffraction results. The bio-reduction rate of silver ions was very slowly up to 1h however, the color changes completed after 5h and resulted in the appearance of the absorbance peak around 430 nm. Moreover, the wound dressing was treated with biosynthesized silver nanoparticles by the exhaustion method and they showed good antibacterial activity.